Ultra-high-temperature heat pump. Gdańsk Tech leads the DUOHEAT project | Gdańsk University of Technology

The project aims to develop, test and prepare for commercialisation an ultra-high-temperature heat pump capable of generating heat at temperatures of up to 200°C. This ambitious undertaking involves significant scientific and technological risks, as achieving such a substantial increase in temperature remains beyond the capabilities of commercially available solutions today.

A key feature of the device under development will be the so-called temperature lift, i.e. the difference between the heat source and the heat sink temperatures. In the case of the DUOHEAT pump, this is expected to be at least 100 K. This means that low-temperature waste heat can be raised to a level at which it can be reused in demanding industrial processes.

This solution can be used, among other things, in the food industry, e.g. during drying and pasteurisation, in the timber industry for drying wood, and also in the chemical industry in processes requiring heating. “In many industrial processes, significant amounts of waste heat are irrecoverably ‘dumped’ into the environment, for example in the form of hot air at a temperature of around 100°C or steam. As part of our project, by using a heat pump, we plan to recover this unused energy. Raising the temperature of the waste heat by at least 100°C will enable it to be reused in industry,” said Prof. Dariusz Mikielewicz, Vice-Rector for Research, Director of the Institute of Energy and Project Manager.

From research to prototype

Work on the device will involve comprehensive experimental, analytical and numerical research. Researchers will focus on the key components of the future system, including the compressor, heat exchangers and the selection of a suitable working fluid. Phase transitions and two-phase flows occurring during the device’s operation will also be analysed.

The project is being implemented by a consortium led by the Gdańsk University of Technology. The consortium members are also the AGH University of Kraków and the Institute of Fluid-Flow Machinery at the Polish Academy of Sciences.

The compressor is the heart of the system

One of the most important components of the pump under design will be a high-speed, oil-free, high-efficiency centrifugal compressor. The use of oil-free bearings and seals is intended to reduce energy losses, simplify operation and eliminate the risk of leaks of substances harmful to the environment.

The design of the compressor will have a direct impact on the efficiency of the entire system and the ability to achieve the target temperature parameters.

Caring for the environment

A key aspect of the research will be the selection of the working fluid, i.e. the substance which circulates through the pump’s system and is responsible for the transfer of thermal energy.

“Another key element is the choice of the working medium. As the Project Manager, my aim is for the medium to be natural and organic, and with no adverse impact on the environment,” added Prof. Mikielewicz. The choice of a suitable medium will need to take into account not only its thermodynamic properties, but also its safety in use and its environmental impact.

A second life for waste heat

DUOHEAT is intended to contribute to the development of an economy based on more sustainable heat production. Recovering energy that is currently lost can reduce fuel consumption, cut emissions and improve the energy efficiency of industrial processes.

Technology can also support the electrification of industry, i.e. the replacement of fuel-combustion-based processes with solutions that use electricity. Integrating heat production with the electricity grid can facilitate better use of energy from renewable sources and, in the future, also from the nuclear power plants planned for Poland.

Work on the project will continue until 29 March 2029.

The project entitled ‘Implementation of an innovative two-stage heat pump for the electrification of high-temperature thermal processes – DUOHEAT’ is funded by the Foundation for Polish Science from the ‘European Funds for a Modern Economy’ (FENG) programme. Amount of funding: PLN 10,992,912.95.